Theoretical Aspects of Charge Ordering in Molecular Conductors

Abstract

Theoretical studies on charge ordering phenomena in quarter-filled molecular (organic) conductors are reviewed. Extended Hubbard models including not only the on-site but also the inter-site Coulomb repulsion are constructed in a straightforward way from the crystal structures, which serve for individual study on each material as well as for their systematic understandings. In general the inter-site Coulomb interaction stabilizes Wigner crystal-type charge ordered states, where the charge localizes in an arranged manner avoiding each other, and can drive the system insulating. The variety in the lattice structures, represented by anisotropic networks in not only the electron hopping but also in the inter-site Coulomb repulsion, brings about diverse problems in low-dimensional strongly correlated systems. Competitions and/or co-existences between the charge ordered state and other states are discussed, such as metal, superconductor, and the dimer-type Mott insulating state which is another typical insulating state in molecular conductors. Interplay with magnetism, e.g., antiferromagnetic state and spin gapped state for example due to the spin-Peierls transition, is considered as well. Distinct situations are pointed out: influences of the coupling to the lattice degree of freedom and effects of geometrical frustration which exists in many molecular crystals. Some related topics, such as charge order in transition metal oxides and its role in new molecular conductors, are briefly remarked.

21 pages, 19 figures, to be published in J. Phys. Soc. Jpn. special issue on "Organic Conductors"; figs. 4 and 11 replaced with smaller sized file

References in corpus (6)

• Tomonaga-Luttinger parameters for doped Mott insulators
• Quantum Melting of Charge Order due to Frustration in Two-Dimensional Quarter-Filled Systems
• Coexistence of Charge Order and Spin-Peierls Lattice Distortion in One-Dimensional Organic Conductors
• Charge order and superconductivity in a two-dimensional triangular lattice at n=2/3
• Phase Diagram of the $t$--$U$--$V_1$--$V_2$ Model at Quarter Filling
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Cited by in corpus (46)

• Electrodynamics of Correlated Electron Materials
• Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors
• Strong electronic correlations in superconducting organic charge transfer salts
• Absence of charge order in the dimerized κ-phase BEDT-TTF salts
• Exact diagonalization study of Mott transition in the Hubbard model on an anisotropic triangular lattice
• Evidence for Lattice Effects at the Charge-Ordering Transition in (TMTTF)${}_2$X
• Extended Hubbard model: Charge Ordering and Wigner-Mott transition
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• Power-law dependence of the optical conductivity observed in the quantum spin-liquid compound κ-(BEDT-TTF)2Cu2(CN)3
• One-dimensional extended Hubbard model in the atomic limit
• Photoinduced melting of charge order in a quarter-filled electron system coupled with different types of phonons
• Towards the parameterisation of the Hubbard model for salts of BEDT-TTF: A density functional study of isolated molecules
• Direct Observation of Mono-, Bi-, and Tri-layer Charge Density Waves in 1T-TaS_2 by Transmission Electron Microscopy without a Substrate
• Electronic properties of Fabre charge-transfer salts under various temperature and pressure conditions
• Finite-Temperature Phase Diagram of Quasi-One-Dimensional Molecular Conductors: Quantum Monte Carlo Study
• Non-local correlations in metals close to a charge order insulator transition
• Charge ordering in θ-(BEDT-TTF)2RbZn(SCN)4: Cooperative effects of electron correlations and lattice distortions
• Phase Competition and Superconductivity in $\kappa$-(BEDT-TTF)${}_2$X: Importance of Intermolecular Coulomb Interactions
• Temperature-driven transition from the Wigner Crystal to the Bond-Charge-Density Wave in the Quasi-One-Dimensional Quarter-Filled band
• Metal-Insulator Transition in the Dimerized Organic Conductor $\kappa$-(BEDT-TTF)${}_2$Hg(SCN)${}_2$Br
• Charge-Ordered State versus Dimer-Mott Insulator at Finite Temperatures
• Spin and Charge Fluctuations and Lattice Effects on Charge Orders in α-(BEDT-TTF)_2I_3
• Correlation-driven electronic multiferroicity in (TMTTF)${}_2$-$X$ organic crystals
• Unconventional metallic conduction in two-dimensional Hubbard-Wigner lattices
• Spin excitations in the quasi-two-dimensional charge-ordered insulator $\alpha$-(BEDT-TTF)${}_2$I${}_3$ probed via ${}^{13}$C NMR
• Double Exchange Ferromagnetism in the Peierls Insulator State
• Electronic States of Single-Component Molecular Conductors [M(tmdt)2]
• Photo-Induced Dynamics in Charge-Frustrated Systems
• Multi-Orbital Molecular Compound (TTM-TTP)I_3: Effective Model and Fragment Decomposition
• Fragment Model Study of Molecular Multi-Orbital System $X$[Pd(dmit)${}_2$]${}_2$
• Optical and spectral properties of quantum domain-walls in the generalized Wigner lattice
• Anomalous scaling law for thermoelectric transport of 2D-confined electrons in an organic molecular system
• Spiral charge frustration in molecular conductor (DI-DCNQI)2Ag
• Magnetic Field Effect in One-Dimensional Charge Ordering Systems
• Phase competitions and coexistences in quasi-one-dimensional molecular conductors: exact diagonalization study
• Quantum Monte Carlo Study of the Quasi-One-Dimensional Superconductivity
• Photoexcitation of a polarization-inverted domain from the charge-ordered ferroelectric ground state of (TMTTF)${}_2$PF${}_6$
• Charge Dynamics in a Correlated Fermion System on a Geometrically Frustrated Lattice
• Superlattice Induced by Charge Order in the Organic Spin Chain (TMTTF)${}_{2}X$ ($X=$ SbF${}_6$, AsF${}_6$ and PF${}_6$) Revealed by High Field EPR
• Combined X-ray diffraction, electrical resistivity, and $ab$ $initio$ study of (TMTTF)${}_2$PF${}_6$ under pressure: implications to the unified phase diagram
• Ferrimagnetism Induced by Off-Site Coulomb Interaction in an Itinerant Electron System
• Thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator ${\beta }^{\prime }$-(BEDT-TTF)${}_2$ICl${}_2$
• Third-order Electrical Conductivity of the Charge-ordered Organic Salt $\alpha$-(BEDT-TTF)${}_2$I${}_3$
• Comparison of the charge-crystal and charge-glass state in geometrically frustrated organic conductors studied by fluctuation spectroscopy
• Stability of correlated insulating states in molecular conductors from first-principles calculation
• Finite-temperature phase transitions in quasi-one-dimensional molecular conductors